摘要: The function and mechanism of exogeneous β-aminobutyric acid (BABA) in protecting tobacco against heat stress were studied through a combination of antioxidant measurements and the transcript characterization on heat shock proteins (HSPs) in treated leaves. The results showed that tobacco leaves without BABA treatment became yellowing and wilting under heat stress, whereas 0.2 mmol/L BABA applied to the leaves could effectively alleviate this situation. Tobacco leaves with BABA treatment contained higher levels of glutathione (GSH), hydrogen peroxide (H₂O₂), and had higher activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) and catalase (CAT), but lower level of malondialdehyde (MDA) and proline, when compared to tobacco group without BABA treatment. Semi-quantitative RT-PCR (Reverse transcription-PCR) results showed that the transcript level of NtHSP101 was up-regulated by BABA treatment under heat stress; but other heat shock protein genes, NtHSP70, NtHSP17.4 and NtLHS had similar levels of transcription between the control and the treatment samples. It was concluded that 0.2 mmol/L BABA treatment was beneficial in relieving heat stress damage on tobacco plants, which probably involved stimulating the antioxidant system and up-regulation of NtHSP101.